Design Patterns Course Requirements

Before starting a course on software design patterns, it's beneficial to have a solid understanding of several foundational topics. Here are the key knowledge requirements:

1. Basic Programming Skills:
   • Proficiency in at least one programming language (e.g., Java, C++, Python, etc.).
   • Understanding of object-oriented programming (OOP) concepts such as classes, objects, inheritance, polymorphism, encapsulation, and abstraction.
2. Data Structures and Algorithms:
   • Knowledge of common data structures (e.g., arrays, linked lists, stacks, queues, hash maps, trees).
   • Familiarity with basic algorithms, including sorting, searching, and recursion.
3. Software Development Principles:
   • Understanding of basic software engineering principles like DRY (Don't Repeat Yourself), KISS (Keep It Simple, Stupid), and SOLID principles.
   • Awareness of the software development lifecycle, including requirements gathering, design, development, testing, and maintenance.
4. Experience with Object-Oriented Design:
   • Experience in designing classes and interfaces with a focus on reusability and maintainability.
   • Knowledge of how to identify and define relationships between objects, such as inheritance and composition.
5. Basic Understanding of UML (Unified Modeling Language):
   • Familiarity with UML diagrams like class diagrams, sequence diagrams, and use case diagrams, as these are often used to illustrate design patterns.
6. Familiarity with Common Architectural Patterns:
   • Basic knowledge of architectural patterns like MVC (Model-View-Controller) or layered architecture is helpful, as they are related to design patterns.

Having a good grasp of these areas will prepare you to understand and effectively apply software design patterns in real-world scenarios.

Since you will be writing either C++ or Java, you will need at least a text editor and a compiler for your language of choice.
If you prefer to use an (IDE) Integrated Development Environment like Microsoft Visual C++ or code.visualstudio.com then do so. However, we will not be designing a graphical user interface, so a simple character mode environment like Oracle's JDK or emacs is all that is required.

1. For those of you experienced with Java you can download the latest version of Eclipse eclipse-packages
2. To download the JDK visit Oracle JDK
3. To download the C++ compiler from Microsoft visit visualstudio.com Downloads

Concrete examples and exercises will all be pure character mode, using the basic I/O facilities common to all languages and operating systems.
You should be able to complete this course using a Windows or Linux operating Stick to pure ANSI C++ or 100% pure Java.

Venturing into the realm of Design Patterns is akin to embarking upon a grand and profound journey. It's not a mere meander into the technicalities of software development, but rather a deep dive into its soul and essence. But as with any transformative journey, there are certain prerequisites, both of the heart and of the mind, that one must possess to ensure not just comprehension but a profound resonance with the subject. Analyzing these requirements reveals the following insights:

1. Passion for the Craft: Above all, a burning passion for software development acts as the primordial fuel for this journey. Without a deep love for the craft, design patterns might appear as mere abstract constructs, devoid of life. It is this emotional connection that turns the study from a mere academic exercise into a life-altering experience.
2. Solid Foundations in Object-Oriented Programming (OOP): At the cerebral level, before one dances with the intricate choreography of design patterns, a firm grounding in OOP is indispensable. Concepts like encapsulation, inheritance, polymorphism, and abstraction are the cornerstones upon which the majestic edifice of design patterns stands. Only with a deep understanding of these can one truly appreciate the analytical beauty and symmetry of patterns.
3. Analytical Problem-Solving Skills: The heart of design patterns lies in solving recurring software design challenges. Hence, an inherent ability or at the very least, a cultivated skill of analytical problem solving is paramount. It's not just about understanding the solution, but about feeling the pain of the problem, analyzing its facets, and then marveling at the elegance of the pattern that addresses it.
4. Experiential Understanding of Real-World Software Development: While theoretical knowledge has its place, there's an emotional depth and analytical clarity that comes from hands-on experience. Having grappled with the complexities of real-world software projects, one is better poised to appreciate the true value of design patterns. They cease to be abstract solutions and become living, breathing answers to the developer's heartfelt challenges.
5. Openness to Continuous Learning: The world of design patterns is vast and ever-evolving. It demands a certain humility and openness to continuous learning. One must come with an analytical mind, but also with an emotional readiness to accept that there's always more to learn, more to assimilate, and more to apply.

In summation, the journey into design patterns is a confluence of emotional passion and analytical rigor. It is a voyage that demands both a heartfelt connection to the craft and a keen analytical mind ready to dissect and comprehend. So, before one takes the leap, it is essential to ensure that both the heart and the mind are adequately prepared, for it is this combination that will lead to true enlightenment in the realm of design patterns.

Before diving into the study of design patterns, a software engineer should have a solid grasp on several foundational concepts and skills. Here are the key prerequisites:

1. Object-Oriented Programming (OOP):
   • Classes and Objects: Understanding how to define classes, create objects, and use inheritance, polymorphism, encapsulation, and abstraction.
   • Inheritance: How to extend classes and the implications of inheritance hierarchies.
   • Polymorphism: The ability of objects of different classes to respond to the same method call, each in its own way.
2. Programming Languages:
   • Proficiency in at least one object-oriented programming language like Java, C++, C#, or Python. Knowledge of how these languages implement OOP concepts.
3. Basic Software Design Principles:
   • SOLID Principles: Single Responsibility, Open/Closed, Liskov Substitution, Interface Segregation, and Dependency Inversion.
   • DRY (Don't Repeat Yourself): Understanding how to avoid redundancy in code.
   • YAGNI (You Aren't Gonna Need It): Focusing on current needs rather than future possibilities that might not occur.
4. Understanding of Software Architecture:
   • Basic concepts of software architecture like modularity, coupling, cohesion, and separation of concerns.
   • Familiarity with architectural patterns like MVC (Model-View-Controller), Layered Architecture, etc.
5. Data Structures and Algorithms:
   • Knowledge of common data structures (arrays, lists, stacks, queues, trees, graphs) and algorithms (sorting, searching, etc.) to understand the efficiency implications of design patterns.
6. Software Development Lifecycle (SDLC):
   • An overview of how software is developed, from requirements gathering through to maintenance, to understand where design patterns fit into the lifecycle.
7. Problem-Solving Skills:
   • Ability to analyze problems, break them down into components, and think about solutions in terms of design and implementation.
8. Experience with Real-World Projects:
   • Practical experience in developing software, even if small projects, helps in understanding real-world problems where design patterns are applicable.
9. Concurrency and Parallelism:
   • Basic understanding of how concurrent programming works, especially if looking into patterns like Observer or Singleton in multi-threaded environments.
10. Testing and Debugging:
    • Knowledge of unit testing, integration testing, and debugging techniques, as design patterns often aim to make code more testable and maintainable.

Understanding these areas will provide a software engineer with the necessary context to appreciate why design patterns exist, how they solve specific problems, and how to apply them effectively in software development. Design patterns are not just about knowing the patterns themselves but knowing when and why to use them, which requires a good foundation in these prerequisites.

The purpose of this course is to record experience in designing object-oriented software as design patterns. Each design pattern systematically names, explains, and evaluates an important and recurring design in object-oriented systems. Our goal is to capture design experience in a form that people can use effectively. To this end we have documented some of the most important design patterns and present them as a catalog. Design patterns make it easier to reuse successful designs and architectures while expressing proven techniques as design patterns makes them more accessible to developers of new systems. Design patterns help you choose design alternatives that make a system reusable and avoid alternatives that compromise reusability. Design patterns can improve the documentation and maintenance of existing systems by furnishing an explicit specification of class and object interactions and their underlying intent. In addition, design patterns help a designer obtain the correct design faster.